<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Math</title>
</head>
<body>
    <script>
        document.write(Math.PI + '<br>');
        document.write(Math.random() + '<br>');
        document.write(Math.round(3.14) + '<br>');
        document.write(Math.ceil(3.14) + '<br>');
        document.write(Math.floor(3.14) + '<br>');

        // 1-100的随机数
        let number = Math.floor((Math.random() * 100))+1;
        document.write(number);

    </script>
</body>
</html>